MySpace (2007) 60,104,000 (2006) 55,256,000

Facebook (2007) 22,574,000 (2006) 13,110,000

Classmates Online (2007) 10,748,000 (2006) 11,406,000

Windows Live Spaces (2007) 8,856,000 (2006) 8,703,000

AOL Hometown (2007) 6,853,000 (2006) 9,032,000

Club Penguin (2007) 6,358,000 (2006) 2,688,000

LinkedIn (2007) 4,804,000 (2006) 2,072,000

Reunion.com (2007) 4,090,000 (2006) 4,327,000

AOL Community (2007) 4,069,000 (2006) 5,213,000

Flixster (2007) 3,097,000 (2006) 744,000

A few Sourcing tips from them:

Your most valuable sourcing method is Site: So ???..

For AOL Hometowns use the Site:hometown.aol.com

http://www.google.com/search?hl=en&q=site%3Ahometown.aol.com+resume

Same for Windows Live: Site:spaces.live.com (add info

http://www.google.com/search?hl=en&q=site%3Aspaces.Live.com+resume

LinkedIN: Site:linkedin.com

http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=site%3Alinkedin.com+information+architect&spell=1

It is better if you build the string in altavista (advanced) as opposed to google.